The hyperlipidemia of pregnancy consists of a 3-fold rise in triglyceride and quarter-fold rise in phospholipids and cholesterol. The rat has been characterized as a good model for the hyperlipidemia of pregnancy and will be further utilized for metabolic studies. Specifically, the effects of high carbohydrate and high fat feeding on the hyperlipidemia will be assessed with attention to correlative levels of glucagon and insulin achieved in portal blood. The hypothesis in this instance is to determine if the hormonal metabolic set is resistant to further perturbation by diet as suggested by our studies in human pregnancy. In an effort to establish the hormonal basis for the hyperlipidemia of pregnancy, the next step will be to give extradiol benzoate, progesterone, and choriomic somatomammotropin individually and in various combinations. Studies will be done of lipoprotein composition, labelled very low density lipoprotein removal from plasma, and tissue lipid uptake. The responses of these parameters and of insulin and glucagon to dietary pertuubations will also be studied in these controlled hormonal conditions. The prediction is that progesterone and estrogen have opposing effects on lipoprotein lipid removal. The effect of HCS is as yet unevaluated apart from its effect as a fat mobilizing and insulinogenic substance. Any difference between the integrated hormonal effect and pregnancy per se may be attributable to the metabolic drain of the fetus on maternal fuels. Finally, descriptive studies will be continued in human pregnancy of sequential changes in lipoprotein lipids and apoproteins. Similar studies in abnormal pregnancies will be done wherever possible. BIBLIOGRAPHIC REFERENCES: Komaroff, A.L., Flatley, M.D., Browne, H., Sherman., S.E., Fineberg, and R.H. Knopp: Quality, efficiency, and cost of a physician assistant-protocol system for management of diabetes and hypertension (Diabetes, 1976). Knopp, R.H., Brandt, K., and Arky, R.A.: Effects of aspartame in young persons during weight reduction. J. Toxicol. Environ. Health (1976) (in press).